Apparatus for lubrication of compression tools for powder metallurgical purposes

ABSTRACT

THERE IS PROVIDED AN APPARATUS FOR THE LUBRICATION OF COMPRESSION TOOLS FOR POWER METALLURGICAL PURPOSES COMPRISING A LOWER DIE ADAPTED TO SUPPLY LUBRICANT FILM, A GUIDE FOR THE LOWER PART HAVING A SLIGHTLY LARGER DIAMETER TO INSURE PRODUCTION OF A UNIFORM LUBRICANT FILM AND A FOOT ON THE OPPOSITE END OF THE DIE POSITIONED WITHIN A SLIGHTLY LARGER DISTANCE RING WHICH IS HELD IN POSITION BY A FIXING NUT, THE SPACE BETWEEN THE DIE FOOT AND FIXING NUT   COMPENSATING FOR PRODUCTION ERRORS IN THE AXIS PARALLELISM OF THE DIE BORE.

July 11, 1972 RQEPENACK ETAL 3,676,030

APPARATUS FOR LUBRICATION OF COMPRESSION TOOLS FOR POWDER METALLURGICALPURPOSES Filed Oct. 22, 1969 z Sheets-Sheet 1 'I T I OI'II 1' 'I if I 'Il l I 10 f'fiI Z 'II ,C

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APPARATUS FOR RIC 0N OF COM ESSION TOOLS FOR Pow METALLURGICAL P OSESFiled Oct. 22, 1969 2 Sheets-Sheet Z 17:85)" EMF/[M406 Jar/5e A amzfe'a'z Pzaaze wd a m ATTORN United States Patent Oflice 3,676,030Patented July 11, 1972 US. Cl. 425-48 Claims ABSTRACT OF THE DISCLOSUREThere is provided an apparatus for the lubrication of compression toolsfor power metallurgical purposes comprising a lower die adapted tosupply lubricant film, a guide for the lower part having a slightlylarger diameter to insure production of a uniform lubricant film and afoot on the opposite end of the die positioned within a slightly largerdistance ring which is held in position by a fixing nut, the spacebetween the die foot and fixing nut compensating for production errorsin the axis parallelism of the die bore.

In powder metallurgical technology powders which are desired to bepressed into molded bodies are preferably mixed with organic additives(lubricants) to make them machjnable. The lubricant addition isnecessary because of the friction between the powder and tool. Thefraction of the necessary lulbricants, which must be especiallyuniformly mixed, is generally so high that in addition to this workingstep a further processing step is necessary, namely a dewaxing ignitionof the sinter. With appropriate molded bodies, the lubricant additivecan be replaced by a lubrication of the compression mold wall. Such aprocedure assumes to be sure that the compression tool is manufacturedand installed with high precision.

This demand is only with difiiculty fulfilled, especially with the useof multiple compression tools which with each compression processmanufacture a multiple number of molded bodies. Also with only slightdeviation in the lubricant film thickness there results in the moldedbodies because of dilferent wall frictions dilferent local densities,which after sintering lead to deviations from the desired shape, or incase of greater deviations lead to increased scrap through cracking andfissures of the sintered bodies.

To lubricate the compression mold, there is used, for example, a lowerdie with an axial bore through which a lubricant solution can enter frombelow. Near the top of the lower die the lubricant passes through radialbores to the outside and wets the mold wall with the upward and downwardmotion during the pressing.

Also in these cases a uniform lubricant film is not always producedbecause of the flaws in the tool production and in the fitting bringabout substantial deviations to only a 10 to 20 p.111. thick lubricantfilm.

It has now been found that these flaws can be substantially reduced whenthe lower die of the tool has a guide part which compensates for theproduction flaws in the tools and in the fitting.

Preferably the longitudinal length of the guide part is greater than thediameter of the mold bore. It is especially suitable for such length tobe one to three times the diameter of the mold bore.

The invention will be understood best in connection with the drawingswherein the single figure is a longitudinal sectional view of theapparatus of the invention.

Referring more specifically to the drawing there is provided acompression die which includes an end portion which is attached to aguide body 2 through an intermediate member 3.

The lubricant flows out in the space between the disc guide member 2 andthe compression die end portion 1 through radial bore holes 8.

The diameter of end portion 1 is so selected that a lubricant film ofpreferably 10-20 #111. can be built between it and the wall 10 of mold11. In order to guarantee an equal gap, the longitudinal length of guideportion 2 is larger than the diameter of the mold bore, preferably 1 to3 times larger than that diameter. Guide portion 2 besides can fulfill ascaling function as can be seen from the drawings where gasket 12 isprovided. In automatic lubrication processes other than that shown inthe drawing the guide portion 2 can be provided with grooves. Theapparatus of the invention not only allows the lubrication ofcompression tools for circular cylinders but also for other suitableshapes. Guide 2 compensates for eventual fitting flaws present while asuitable support or foot 4 of the die as necessary to take care ofdeviations in axis parallelism of the mold bore which almost alwaysoccur in multiple tools. Typical examples of such multiple tools areshown in drawing 2. Support 4 is surrounded by a structure 13 which ismoveable to and away from mold 11. Support 4 is mounted so that the diecan move according to the deviations of axis parallelism in theproduction of the lubricant film. This can be accomplished, for example,by employing a distance ring or spacer ring 5. The inner diameter ofring 5 is somewhat greater, preferably 0.5 to 1 mm., than the diameterof the die foot 4 and whose height is 0.1 to 0.2 mm. greater than thatof the die foot. The distance ring is held in its position by the fixingout 6. The fixing not 6 terminates in turn the axial motion of the diein an upward direction.

What is claimed is:

I1. An apparatus for the lubrication of compression tools for powdermetallurgical purposes comprising a mold having a bore therein, astructure mounted for relative movement toward and away from said mold,a die connected to said structure having a die part disposed within saidbore, said die part comprising a first end portion, a guide portion forsaid end portion, means between said first end portion and said guideportion for supplying lubricant to the mold, said guide being of largerdiameter than said first end portion to insure production of a uniformfilm on said mold, an opposite end portion on said die, and meanspermitting radial movement of said opposite end portion wherebycompensation can be made for production errors in the axis parallelismof the mold bore.

2. An apparatus according to claim 1 wherein said radial movementpermitting means comprises a distance ring slightly larger than anddisposed around said opposite end portion and a fixing nut adjacent saiddistance ring and holding it in position.

3. An apparatus according to claim 2 wherein the longitudinal length ofthe guide portion is 1 to 3 times greater than th diameter of the moldbore.

4. An apparatus according to claim 1 wherein the guide has the samemaximum diameter as the mold bore.

5. An apparatus according to claim 4 wherein the longitudinal length ofthe guide portion is l to 3 times greater than the diameter of the moldbore.

6. An apparatus according to claim 1 wherein said radial movementpermitting means comprises a distance ring slightly larger than anddisposed around said opposite end portion and a fixing nut adjacent saiddistance ring and holding it in position and wherein said lubricantsupplying means includes an aperture in said die part for supplyinglubricant and the diameter of said die part is 20 to 40 m. smaller thanthe diameter of the guide portion.

7. An apparatus according to claim 1 wherein said radial movementpermitting means comprises a distance ring slightly larger than anddisposed around said opposite end portion and a fixing nut adjacent saiddistance ring and holding it in position and wherein a space is providedbetween the fixation nut and the opposite end portion to permit an axialplay of 0.1 to 0.2 mm.

8. Apparatus for the lubrication of compression tools for powdermetallurgical purposes comprising: mold means defining a plurality ofparallel spaced-apart mold cavities; a plurality of dies each having afirst end portion slidably disposed in one of said mold cavities, andeach die including internal passage means for supplying a uniform filmof lubricant to the wall of its respective cavity; a structure mountedfor movement toward and away from said mold means; and means connectingthe opposite end portions of each die to said movable structure formovement relative thereto in a plane transverse to the axes of the diesand for movement with said structure toward and away from said moldmeans.

9. Apparatus as in claim 8 wherein said connecting means includes aportion of enlarged diameter on each of said dies, a plurality ofdistance rings each slightly larger than and disposed around one of saidenlarged portions thereby permitting relative movement between eachenlarged portion and its respective ring means for retaining eachenlarged portion within its respective distance ring.

10. Apparatus as in claim 9 wherein each said retaining means includes anut surrounding one of the dies and threadedly engaging said movablestructure, said nut clamping the respective distance ring to thestructure and being spaced from the enlarged portion of the respectivedie to permit a longitudinal play of 0.1 to 0.2 mm. between the die andsaid structure, each of said distance rings having an internal diameterwhich is 0.5 to 1 mm. greater than the diameter of the respectiveenlarged die portion.

References Cited UNITED STATES PATENTS 2,810,929 10/1957 Willi 18--16.72,932,063 4/ 1960 Belden et a] 18-165 3,132,379 5/1964 Crane 18-1653,149,375 9/1964 Gehl 1816.5 3,200,442 8/1965 Haller 18-165 3,394,4327/1968 Lament l8--16.5

J. HOWARD FLINT, JR., Primary Examiner US. Cl. X.R. 425-96, 345

